The dramatic increase of popularity of the Internet has led to a corresponding dramatic rise in the popularity of textual communications such as e-mail and instant messaging. Increasingly, browsing of the World Wide Web of the Internet and textual communications are being performing using reduced keypads such as those found on mobile telephones.
Multi-tap systems provide usable but less than convenient text entry functionality for users of the Roman or similar alphabet. Briefly, multi-tap systems determine a number of repeated presses of a key to disambiguate multiple letters associated with a single key. For example, pressing the “2” key once represents the letter “a;” pressing the “2” key twice represents the letter “b;” pressing the “2” key thrice represents the letter “c;” and pressing the “2” key four (4) times represents the numeral “2.” The number of presses of a particular key is typically delimited with a brief pause. While feasible, entering textual data of the Roman alphabet using multi-tap is cumbersome and time-consuming.
Some attempts have been made to use predictive interpretation of key presses to disambiguate multiple written symbols associated with individual keys. Such predictive interpretation is described by Zi Corporation on the World Wide Web and in U.S. Pat. No. 5,109,352 to Robert B. O'Dell (hereinafter the O'Dell Patent). Predictive interpretation is generally effective and greatly simplifies text input using reduced keypads with very large collections of written symbols. However, predictive interpretation has difficulty with words used in proper nouns, slang, and neology as such words might not be represented in a predictive database.
Despite its great efficiency, predictive interpretation of key presses for disambiguation provides a somewhat less than intuitive user experience. In particular, predictive interpretation, lacks accuracy until a few characters have been specified. The following example is illustrative.
Consider that a user is specifying the word “forest” using a numeric telephone keypad. In predictive interpretation, the user presses the following sequence of keys: 3-6-7-3-7-8. It should be appreciated that entering “forest” using multi-tap is significantly more cumbersome, pressing 3-3-3-6-6-6-7-7-7-3-3-7-7-7-7-8. Entry of text in which two or more consecutive letters are presented by the same key is exacerbated by the need to pause for a period of time between specifying each such letter to delimit the respective letter. In predictive interpretation, pressing “3” by the user does not necessarily interpret and display “f” as the indicated letter. Instead, an “e” or a “d” could be displayed to the user as the interpretation of the pressing of the “3” key. In some predictive interpretation implementations, the entire predicted word is displayed to the user. Since numerous words begin with any of the letters d, e, or f, it is rather common that the predicted word is not what the user intends to enter. Thus, as the user presses the “3” key to begin spelling “forest,” an entirely different word such as “don't” can be displayed as a predicted word.
As the user presses the second key in spelling “forest,” namely, the “6” key, some word other than “forest” can continue to be displayed as the predicted word. What can be even more confusing to the user is that the predict word can change suddenly and dramatically. For example, pressing the “6” key can change the predicted word from “don't” to “eminently”—both of which are spelled beginning with the “3” key followed immediately by the “6” key—depending upon frequency of usage of those respective words. To obtain full efficiency of predictive interpretation systems, the user continues with the remainder of the sequence—finishing with 7-3-7-8. Once the full sequence is entered, only one word—or just a few words—match the entered sequence. However, until that point is reached, the user is required to place faith and trust that the predictive interpretation will eventually arrive at the correct interpretation notwithstanding the various displayed incorrect interpretations early in the spelling of the desired word.
What is needed is an improved mechanism for efficiently disambiguating among multiple symbols associated with individual keys of a reduced keypad while continuing to provide accurate and reassuring feedback to the user.